Device for producing separator pockets for electrical accumulator plates

ABSTRACT

Apparatus for making separator envelopes for electrical battery plates having a device for folding an ultrasonically weldable polymeric web around individual battery plates and a device for feeding filled separator envelopes to ultrasonic welding devices, The feed device being provided with two endless synchronously driven feed belts (4, 8) above and below a horizontal feed plane (H) for the separator envelopes (S) as well as symmetrically relative to a longitudinal center plane of the apparatus, which feed belts, with their loops extending parallel to the feed plane, together engage lateral portions of the separator envelopes and which continuously pull the superposed lateral margins of the separator envelopes protruding beyond the feed belts through the ultrasonic welding device.

The invention relates to an apparatus for making separator envelopes forelectrical battery plates, comprising a device for folding sections ofan ultrasonically weldable polymeric web over individual battery platesand a device for feeding filled separator envelopes to ultrasonicwelding devices where the superposed open side margins of the separatorenvelope are welded together.

In known apparatus for wrapping battery plates, the separator envelopesfolded over individual battery plates and open at their sides areintermittently guided to an ultrasonic welding device consisting of alower horn and an upper anvil. The lateral margins to be connected arepressed between the horn and the anvil, and the ultrasonic weldingconnection is produced by an ultrasonic impulse of predetermined energyand duration. The significant disadvantage of the known apparatusresides in its intermittent process cycle which requires an elaboratecontrol and results in a relatively low production rate.

U.S. Pat. No. 4,026,000 also discloses an apparatus of the kind referredto supra, which operates continuously and thus allows a higherproduction rate. In the known apparatus, the horn cooperates with anoppositely positioned rotary anvil the bias pressure of which may be setby the force of a spring. Feeding of the laterally open separatorenvelopes is accomplished by a pair of superposed rollers which push theseparator envelopes to be welded through the welding device proper. Thisconstruction suffers from the disadvantage that because of their pushfeeding into the welding zone, the side margins of the separatorenvelopes to be welded are subjected to strong stresses, and they areoften damaged.

From U.S. Pat. No. 4,866,914 it is known per se in the field of weldingopen polymeric bags, to pull the open end of the bag through anultrasonic horn arrangement with two endless feed belts engaging the bagon its upper and lower surfaces. The horn arrangement operatesintermittently. Nothing is disclosed by this publication about thespecial problems of two-sided welding of envelopes and, moreparticularly, about any structural solution to the problem ofadjustments to accommodate envelopes of different widths.

The invention is directed to providing an apparatus of the kind referredto supra which while carefully handling the separator envelopes, permitshigh production rates of separator envelopes of different widths weldedon two sides. The apparatus in accordance with the invention ischaracterized by the fact that the feeding device comprises two endlesssynchronously driven feed belts respectively positioned above and belowa horizontal feed plane for the separator envelopes, as well as insymmetry relative to a longitudinal center plane of the apparatus, andtogether engaging, with their loops extending parallel to the feedplane, lateral portions of the separator envelopes and continuouslypulling superposed lateral margins of the separator envelopes protrudingbeyond the feed belts, through the ultrasonic welding devices, the upperand lower feed belts being respectively guided by pulleys in side platesof a machine frame positioned at the intake and output ends, the sideplates of both sides of the machine frame being mounted in the machineframe for adjustment, by an adjustment device, of the width of thewelding margin symmetrically relative to the longitudinal center planeof the apparatus.

By means of the apparatus in accordance with the invention the twosuperposed separator envelopes to be welded together can be pulled intoand out of the ultrasonic welding devices by the feed belts. Since theupper and lower feed belts move in synchronism, the traction force isalways constant. This, at a high production rate and little wear on theapparatus, permits as careful a manipulation as possible of the materialto be welded. In this connection, the feed belt suspension in accordancewith the invention allows the apparatus to be adjusted precisely to thewelded lateral margins width of the separator envelopes to be welded.

In accordance with a preferred embodiment of the invention, the upperand lower feed belts are each guided by pulleys mounted on side platesat the input and output ends of the machine frame, with the side plateson both sides of the machine frame being maintained in the machine framefor adjustment by a calibration device for symmetrically adjusting thewidth of the welding margin relative to the longitudinal center plane ofthe apparatus.

An improved embodiment which makes for an exact guidance of theseparator envelopes through the apparatus, is characterized by theprovision, flush with each feed belt, of a hold-down rail located abovea support affixed to the side plates and constituting the feed plane. Inthe feed direction, the hold-down rail extends forwardly and rearwardlyof the ultrasonic welding device, and is mounted on the supportresiliently biased toward it, with its basic distance from the supportbeing adjustable.

For practical purposes one trimming device each for trimming theseparator envelopes is provided behind the ultrasonic welding devices inthe feed direction.

The invention and further characteristics thereof will hereinafter beexplained in detail on the basis of an embodiment, with reference to thedrawings, in which:

FIG. 1 shows a view in longitudinal section of an apparatus inaccordance with the invention; and

FIG. 2 is a plan view of FIG. 1.

The apparatus shown in the drawings has an input end (arrow E) forsequentially fed separator envelopes S, made, for instance, from apolyethylene foil, each folded around a battery plate and open at itssides and at its trailing end (the folding device and the device forfeeding battery plates are not shown), and an output end (arrow A) forwelded separator envelopes S.

The apparatus consists of two halves which are substantially symmetricalrelative to a vertical center plane V. Side portions 1 of a machineframe supporting all essential components of the apparatus are connectedto each other by a plurality of transverse struts 1'. Above a horizontalfeed plane H and at the input and output ends, each side portion 1supports a set C and a set D of three pulleys 3, 3', 3" each, journalledin side plates 2 and 2'. An endless upper feed belt, formed as a coggedbelt 4 moving in the feed direction F of the separator envelopes S, istrained around the pulleys 3, 3', 3". The cogged pulley 3 of the set Dat the output end is mounted on the drive shaft M of a motor (notshown).

Below the sets C and D, respectively, of cogged pulleys 3, 3', 3" at theinput and output ends a lower cogged pulley 5 and 5' is mounted on eachside plate 2 and 2', pulley 5' being also mounted on a drive shaft M. Alower feed belt which is a cogged belt 8 also is trained around thecogged pulleys as well as further cogged pulleys 6 and a tension roll 7to be described. Together, the cogged belt 8 and the upper cogged belt 4constitute a feed device engaging the lateral portions of the separatorenvelopes S to be welded. The two cogged belts 4, 8 are drivensynchronously by the cogged pulleys 3, 5' and exert on the separatorenvelopes to be welded an always constant traction force.

A horizontal support 9 supporting a hold-down rail 10 for the lateralportions of the separator envelopes S and forming the feed plane H forthe separator envelopes S, is mounted on the side plates 2, 2' at eachside of the machine frame. The hold-down rail is resiliently biasedagainst the support 9 by two spring bias mechanisms 11. The lower loopof the upper cogged belt 4 is running below the hold-down rail 10. Thehold-down rail 10 is positioned flush relative to the cogged pulleys 3,3', 3" and serves to maintain the engagement between the lateralportions of the separator envelopes S grasped between the cogged belts4, 8 at a predetermined pressure set by the springs of the biasingmechanism 11. The margins of the separator envelopes to be weldedtogether and protruding beyond the hold-down rail 10 are drawn throughultrasonic welding device U positioned laterally at each side of themachine frame and outside the hold-down rail 10.. The ultrasonic weldingdevice comprises a vertical lower horn 12 and an upper anvil 13cooperating therewith, the anvil 13 being a continuously rotatingcircular disc rotatably mounted on a common axle with the other anvil ofthe side portions 1 and driven by a drive U'. In the direction forwardlyof and behind the welding device U, the support 10, at its lower surfacesupports the two cogged pulleys 6 guiding the lower loop of the coggedbelt 8.

Each of the,spring bias mechanisms 11 of the hold-down rail 10 comprisesa rocker arm 11"', biased downwardly by a spring 11' and is pivotableabout a pin 11", the bias of the spring 11' being adjustable by a screw11^(iy).

As they consecutively enter the input end E, the separator envelopes S,each loaded with a battery plate, are continuously drawn under the twoparallel hold-down rails 10 by the pairs of cogged belts 4, 8. Thehold-down rails 10 are thus slightly lifted against their spring biasand exert their preset bias against the lateral portions of theseparator envelopes S. The separator envelopes S move through thecontinuously operating ultrasonic welding devices U. Before enteringunder the set D of cogged pulleys at the output end A, the weldedseparator envelopes S, for trimming of their welded lateral margins,move through margin trimming devices T each of which comprises a pair ofupper and lower cutting discs 14 mounted on an axle journalled in theside portions 1 and driven by a drive unit T'. After leaving theapparatus, the separator envelopes S, now closed at three sides, arereceived by an output conveyor B.

In the vicinity of each margin trimming device the tension roll 7 ismounted on a support 15 connected to the associated support 8.

The side plates 2, 2' of the machine frame 1, 1', in which the coggedpulleys are journalled, are symmetrically adjustable relative to thelongitudinal center plane of the apparatus and to each other. To thisend, there is provided a lateral adjustment device 16 including twospindles 17 with opposing threads engaging nuts 18 attached to the sideplates 2, 2', each being actuable by hand wheels 19 for adjusting theside plate 2, 2', including the components supported by them, inparticular the cogged belts 4, 8, to accommodate the width of theapparatus to conform exactly to the width of the separator envelopes Sto be welded together.

As shown in FIG. 1, the cogged pulleys 3', 3" are suspended floatinglyrelative to the side plates 2, 2' about the axis of the upper coggedpulley 3", by an angle iron, to simplify input and output of theseparator envelope.

The welding gap of the ultrasonic welding devices U may be set byvertical adjustment of the horns 12.

It will be understood that within the ambit of the general inventiveconcept the described embodiment may be altered in different ways.

What is claimed is:
 1. An apparatus for making separator envelopes forelectrical battery plates, comprising:machine frame means comprisingsubstantially planar feed path means having an input end and an outputend; ultrasonic welding means positioned on said feed path meansintermediate said input and output ends for ultrasonically welding toeach other superposed opposite margins of polymeric web meansindividually folded over a plurality of battery plates; means forcontinuously feeding said folded web means with said battery platestherebetween along said feed path with said opposite margins aligned inparallel therewith through said ultrasonic welding means, said feedingmeans comprising: first and second pairs of endless belt means extendingbetween said input and output ends and positioned in parallel to eachother on opposite sides of said feed path, one of said belt means ofeach of said first and second pairs being positioned above and the otherof said belt means of said first and second pairs being positioned belowsaid feed path; means for aligning said first and second pairs ofendless belt means with said opposite margins of folded web means; andmeans for driving said endless belt means in synchronism.
 2. Theapparatus of claim 1, wherein said endless belt means is trained aroundpulley means suspended by side plate means respectively positioned atsaid input and output ends on opposite sides of said feed path means. 3.The apparatus of claim 2, wherein at least one of said pulley means atone of said input and output ends comprises a plurality of pulleys atleast one of which is floatingly suspended.
 4. The apparatus of claim 3,further comprising pulley means on opposite sides of, and adjacent, saidwelding means as seen in the direction of feed.
 5. The apparatus ofclaim 4, wherein at least one of said one and said other endless beltmeans is provided with tension means.
 6. The apparatus of claim 2,wherein said means for aligning said endless belt means with saidopposite margins comprises selectively rotatable spindle means havingoppositely threaded end sections positioned symmetrically and normal tothe longitudinal axis of the machine frame means and received incomplementary threaded means in said side plates at said input andoutput ends.
 7. The apparatus of claim 1, wherein said feed path meanscomprises substantially horizontal support means provided with hold-downrail means extending parallel to each other on opposite side of saidfeed path means aligned with said opposite margins and resilientlybiased thereagainst.
 8. The apparatus of claim 7, wherein said hold-downrail means is mounted substantially flush with the endless belt meansabove said feed path means.
 9. The apparatus of claim 8, wherein saidhold-down rail means and said endless belt means extends forwardly andrearwardly of said ultrasonic welding means.
 10. The apparatus of claim1, further comprising, behind said ultrasonic welding means as seen inthe direction of feed, means for trimming said opposite margins.